Currently, failure to persist after transfer into cancer patients is a factor that limits the effectiveness of adoptive cell transfer of T cells genetically modified to express a tumor-reactive T cell receptor. The goal of this application is to modify th human TCR TIL 1383I (melanoma-reactive) by appending the cytoplasmic signaling domains of DAP10 to the end of the cytoplasmic domains of the ?- and ?- chains of the TCR. We believe that the TCR/DAP10 will directly activate the DAP10 pathway upon TCR engagement, and that these unique signals will enhance the survival of transferred T cells. Preliminary data: We have demonstrated in CD8+ T cells that signaling through the [naturally expressed] activation receptor complex NKG2D enhances memory development. Our data show that NKG2D signaling in TCR-transduced CD8+ T cells augments their anti-tumor potency and in vivo persistence. These data argue that signaling through NKG2D in CD8+ T cells is a viable approach to overcoming the limited survival of TCR- Td T cells. We will couple TCR ligation and activation of downstream NKG2D signaling. Because NKG2D is unable to signal by itself, we will use the signaling domain of DAP10, the adaptor molecule that mediates signaling downstream from NKG2D in CD8+ T cells. We will modify the human TCR TIL 1383I (tyrosinase- reactive) by appending the cytoplasmic signaling domains of DAP10 to the end of the TCR cytoplasmic domains of the ?- and ?- chains. Hypothesis: We hypothesize that the TCR/DAP10 will directly activate the DAP10 stimulatory pathway upon TCR engagement, and that these unique signals will enhance the survival of adoptively transferred T cells. Strategy: The retroviral vector containing TCR/DAP10 construct will then be transduced into human T cells. Human T cells expressing TCR/DAP10 will be examined for their signaling pathways, capacity to survive and ability to mediate the regression of established human cancer using a humanized model of melanoma. Immune deficient A2/NSG mice and human melanoma cell lines will be used for anti-tumor experiments. We will test our hypothesis through the following specific aims SA1. Develop TCR/DAP10 constructs to induce and dissect DAP10 signaling. SA2. Study the signaling pathways utilized by TCR/DAP10 and their cellular consequences in human T cells. SA3. Test T cells expressing TCR/DAP10 against human melanoma. The significance and innovative character of our strategy would be that these engineered T cells will have specificity for tyrosinase, and engagement of their TCR will activate the DAP10 costimulatory pathway as well as downstream TCR signaling.